It is known to wash a vehicle parked in a bay by means of one or more spray arms which travel around the vehicle while dispensing various chemicals in streams of water. Reissue Pat. No. 40,463 dated Aug. 26, 2008 and assigned to Belanger, Inc. of Northville, Mich. describes such a system. Inverted L-shaped spray arms which depend from an overhead carriage are supplied with water and chemicals for washing and rinsing and are caused to move around the vehicle to wash the outside surfaces thereof.
The system described in the Reissue patent is reasonably tolerant of positioning errors which result in an off-center vehicle; i.e., the system described in the Reissue patent has the capability of lateral as well as longitudinal translation and can, therefore, adjust its travel to the actual centerline of the vehicle regardless of its position in the bay.
Where that lateral adjustment capability is not present, proper positioning of the vehicle becomes more important. Various mechanisms including dangling objects and laser beams which contact the windshields of the vehicle are known as assists to the driver of a vehicle entering, for example, a residential garage. These devices are not always suitable for use in a spray-type car wash for various reasons.